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Spectral Disentangling Applied to Triple Systems: RV Crt

Spectral Disentangling Applied to Triple Systems: RV Crt. H.Hensberge 1 , L.P. R. Vaz 2 , K.B. Torres 2 , T. Armond 2 1 Royal Observatory of Belgium, Brussels 2 UFMG, Belo Horizonte, Brazil. s pectral Disentangling RV Crt Overview.

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Spectral Disentangling Applied to Triple Systems: RV Crt

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  1. Spectral Disentangling Applied to Triple Systems: RV Crt H.Hensberge1, L.P. R. Vaz2, K.B. Torres2, T. Armond2 1 Royal Observatory of Belgium, Brussels 2 UFMG, Belo Horizonte, Brazil

  2. spectral Disentangling RV CrtOverview • Spectral Disentangling: principles & methods • RV Crt: observations • RV Crt: spectral disentangling applied • RV Crt: fundamental stellar parameters • Conclusions and future work

  3. Spectral Disentangling RV Crt Principles I composite = weighted sum of component spectra # param. > #sp. bins x #components intrinsic component spectra time-independent no notion of individual spectral lines disentangling: solves consistently for Doppler shifts or orbital parameters AND component spectra spectral separation: orbital parameters FIXED

  4. Spectral Disentangling RV Crt Principles II Indeterminacies: Normalised component spectra Only when the relative light contributions of the individual stars depend effectively on time else: contrib. of component to composite spectrum  0.40 x = 0.25 x

  5. Spectral Disentangling RV Crt Principles III Indeterminacies: Ill-determined low-frequency part of component spec. Because of small bias in normalisation of composite spectra non-optimal solution

  6. Spectral Disentangling RV Crt Methods I Velocity space Simon & Sturm 1994 A&A 281, 286 huge set of coupled linear equation (#sp.bins x #obs.spec.) with (#sp.bins x #comp.) unknowns Fourier transf. spectra Hadrava 1995 A&AS 114, 393 (#sp.bins/2 + 1) subsets of #obs.spec. complex equations each with #comp. unknowns

  7. Spectral Disentangling RV Crt Methods I Velocity space Simon & Sturm 1994 A&A 281, 286 huge set of coupled linear equation (#sp.bins x #obs.spec.) with (#sp.bins x #comp.) unknowns Fourier transf. spectra Hadrava 1995 A&AS 114, 393 (#sp.bins/2 + 1) subsets of #obs.spec. complex eq. each with #comp. unknowns Differences computation time weighting / masking response to bias in input data

  8. Spectral Disentangling RV Crt Methods II: codes & info Fourier space KOREL http://www.asu.cas.cz/~had/korel.html FDBinary http://sail.zpf.fer.hr/fdbinary/fd3 Velocity space CRES http://sail.zpf.fer.hr/cres (spec. separ.) Method analysis & applications: ASP Conf. Ser. 318 (2004) Spectroscopically and spatially resolving the components of close binary systems

  9. Spectral Disentangling RV Crt RV Crateris: observations I RV Crt F8 V = 10.2, B = 9.3 uvby photometry 1987-89 61 nights at 0.5m SAT, La Silla, Chile Orbital period: 1.17050239 days (28 h) +/- 21 total primary eclipse Inclination: 89.9 ° third light

  10. Spectral Disentangling RV Crt RV Crateris: observations II 41 FEROS echelle spectra  390 – 900 nm 20 min. exp., S/N = 100 /∆ = 48 000 incl. Primary mid-eclipse 25 selected spectral regions 512 – 4096 bins of 2.7 km/s differential data reduction

  11. Spectral Disentangling RV Crt RV Crateris: components primary underlying spectrum of tertiary

  12. Spectral Disentangling RV Crt RV Crateris: visibility of secondary Na I 589 nm 3 1 2 3 1 2 3 1 1 3 1 3 2 1 3 2

  13. Spectral Disentangling RV Crt RV Crateris: main requirements • measure accurately Doppler shifts of primary and secondary? • reconstruct intrinsic spectrum of 3 comp.? cross-correlation peak from LNA spectra shows triple structure

  14. Spectral Disentangling RV Crt RV Crateris: input data KOREL • KOREL extended to deal with many regions of different sizes • 25 carefully selected spectral regions edges in continuum strong spectral features • KOREL coupled to output of WD code • photometry guides input of light factors out of eclipse • mass ratio from regions with significant contribution of secondary • spectral separation in additional regions

  15. Spectral Disentangling RV Crt RV Crateris: component spectra

  16. Spectral Disentangling RV Crt RV Crateris: rotation Vrot(1) = 49 km/s Vrot(2) = 73 km/s

  17. Spectral Disentangling RV Crt RV Crateris: rotation Vrot(1) = 49 km/s Vrot(2) = 73 km/s

  18. Spectral Disentangling RV Crt RV Crateris: radial velocities

  19. Spectral Disentangling RV Crt RV Crateris: light curve modeling

  20. Spectral Disentangling RV Crt RV Crateris: stellar parameters secondary primary Mass Radius log g Log L T eff. 0.76 (0.01) 1.13 (0.01) 4.21 (0.01) 0.34 (0.03) 6600 (120) 0.41 (0.006) 1.51 (0.01) 3.69 (0.01) -0.21 (0.05) 4200 (120) Msun Rsun K

  21. spectral Disentangling RV CrtConclusions and future work • SD feasible for triple systems even when third light dominates the spectrum • less massive component is larger, cooler and fainter • RV Crt is probably a physical triple • improve SD solution • analyse component spectra • final solution • evolutionary status (pre-MS?)

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